Answer:
13 ft.
Step-by-step explanation:
Lateral Surface area of a cube is the area of 4 sides, front side, back side, left side face and right side face.
It can be seen seen from the attached figure as well.
Each face in a cube is a square. And each side in the cube is equal.
So, Lateral surface area is nothing but 4
area of a square.
And we know that area of a square =
.
Hence, Lateral surface area = 
As per question:
= 676

Hence, side length of cube = 13 feet.
= cos( -x ) * [ - sin( - x ) ] = cosx * sinx ;
cosx * sin x is the right answer !
Answer: b is the answer
Step-by-step explanation: have a nice day